Understand the Torque Control Gain Inconsistent with Peers / Over Time check
What is the purpose of the turbine issue check?
- A given turbine has a torque controller gain that changes over time, either continuously, intermittently, or with discrete change points.
- A given turbine has a torque controller gain that differs from others of the same turbine model at a given site.
Can you see this in 10-min data?
- Yes, this is an issue that can be identified in 10-minute data
What does this look like / How do you identify this issue?
- Torque controller gain controls the power generated when the turbine is operating in region 2 of the power curve. The torque controller gain defines the relationship between rotor speed, torque and power, where the torque is equal to the controller gain times the square of the rotor speed, and power equals torque times rotor speed. The controller gain is nominally a function of the rotor swept area, the tip speed ratio, the turbine radius, the air density and the optimal power coefficient.
- In this case WindESCo identified a discrepancy among different groupings of turbines and was identified by plotting the torque vs. rotor speed curve
How can you tell the issue is corrected?
- The issues is corrected when all of the turbines have a consistent torque gain curve.
- This issue was corrected by identifying incorrect parameter values on the pitch-power table on ¼ of turbines
- In this case, it caused a 0.8% impact to AEP and increased risk of blade damage
- Correction of the issue increased revenue by $50,000 / Yr for the site